I've mostly used S-04, US-05, Nottingham, and I used Windsor once or twice. It's really hard to say what kind of differences they make because I've done them all in such different styles. I did use T-58 once, and plan to use it again soon. It's very mild for a "belgian" yeast, there's a bit of pepper to it but not much fruit. I also just bottled a beer done with S-23 at higher temps (my apartment has been about 74°F on average for the last couple months, which happens to be the temperature at which Stone ferments all their ales), it definitely had some strong yeast character that I'm not sure about. Probably won't try that one again, but we'll see how the finished beer tastes in 3 weeks or so. Oh, also, I have a RIS in primary with S-33, and the hydrometer samples have been encouraging. I feel like I'm pretty happy with S-04, S-33, and T-58, but I've also been thinking about harvesting some wild yeast from the plum tree outside our window. I've got a friend out here who brews with yeast harvested from his sourdough starters, and I had a taste of some of his stuff that was really good.